Better comment the hooks

There seems to be some confusion over how to use hooks now that we symlinked the directory https://github.com/gitlabhq/gitlab-shell/issues/188

These comments should make things more clear.

hooks/post-receive

@@ -3,8 +3,7 @@
 # This file was placed here by GitLab Shell.
 # It is a shared file that is symlinked from all repositories.
 # It makes sure that your pushed commits will be processed properly.
-# You can add your own hooks to by uncommenting the lines at the bottom.
-# If you upgrade GitLab Shell you will have to redo your changes.
+# For instructions on how to add custom hooks see the comment below.
 # Consider using project services of post-receive hooks
 # See http://doc.gitlab.com/ce/integration/README.html
 # Or use web hooks that trigger an external application
@@ -17,16 +16,16 @@ repo_path = Dir.pwd
 require_relative '../lib/gitlab_post_receive'
 if GitlabPostReceive.new(repo_path, key_id, changes).exec
+  ## How to add a custom hooks to some repositories:
+  ## 1) Put a file with custom code in the repository root directory.
+  ## 2) Uncomment the lines below.
+  ## 3) Replace 'project-specific-hook' with the name if the custom file.
+  ## 4) If you upgrade GitLab Shell you will have to redo your changes.
+  #
+  # if File.exists?('project-specific-hook')
+  #   execute 'project-specific-hook'
+  # end
   exit 0
 else
   exit 1
 end
-
-## How to add a custom hooks to some repositories:
-## 1) Put a file with custom code in the repository root directory.
-## 2) Uncomment the lines below.
-## 3) Replace 'project-specific-hook' with the name if the custom file.
-#
-# if File.exists?('project-specific-hook')
-#   execute 'project-specific-hook'
-# end